Stereoscopic projection screen



June 17, 1924. 1,498,433

, c. Boum y SCOPIC P I Filed Ydan. 9.6 19' WM u 2 Sheets-Sheet 1 June 17 1924.

C. BOUIN a sheets-shut' z Filed Jan. 26 1922 5 5 .7J 5 E E 5 5 Patented June 17, 1924.

UNITED STATES 1,498,433 PATENT oFFlcE.

CHARLES BOUIN, OF BOSTON, MASSACHUSETTS.

STEREO'SCOPIC PROJECTION SCREEN.

Application led January 26, 1922. ,Serial No. 531,938.

TooZZ whom 'it may concern:

Be it' knownthat I, CHARLES BOUTN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful`V Improvements in Stereoscoplc Projection Screens, of which the following is a specification. y

The object of this invention being to project ordinary moving picture film images upon a screenof certain specified construction and the results obtained upon viewing said images upon the screen constitutes an improvement.

The invention relates more particularly to a stereosco ic projection screen or, a screen u on which are projected pictures or series o pictures which have been photographed from a single point of direction or position,

such pictures or images being projected from one point of direction and upon viewing the projected images on such a screen r as to be described in detail, space, relief, solidity, etc., will be perceived.

l Further objects and advantages of the present invention will be pointed out in the hereinafter following description of one,A

embodiment hereof, or will be obvious to those skilled in the mentioned arts.

Figure 1 is a top edge view of a screen constructed according to this invention, and

Figure 2 is a front view thereof.

Fig. l, is intended to represent an idea of a'stereoscopic projection screen which is composed of di'erent frustrum rshaped areas which run the whole vertical length of screen as indicated in Fig. 2; the frustrum shaped bodies in Figs. l and`f2, being exaggerated in size for the urpose of being se more easily understood. uch a stereoscopic projection screen with various shaped frustrum bodies being made of any suitable material desired. The projection of images upon such a screen, scribed, being froma point of position as indicated by lin Fig. l. v The frustrum shaped bodies or projections of thek screen vary.in shape from vertically elongated equilateral or isosceles ce triangular frustrums in centre vof screen and gradually changing inv' shape f on approaching-the horizontal margins of screen to right Qrleft verticallyielongated triangular frus- :Jf trumsgacccsding to horizontal' side of centre of. screen, and soon, toj've'rtically .elongated to be more fully dew obtuse-angled triangular frustrums, which are more pronounced as horizontal margins of screen are reached. In other words, the triangular shaped frustrums of the projectionscreen are of such triangular shapedy vfrustrums that they correspond to the crossing of two lines from two points of' about 2% inches apart, the two points being in distance from each other approximately the same as the normal distance of the crossing of such two lines from the two points being approximately the same `as distance of images of scenes or objects in projector to the projection screen, and the approximate distance ofthe eyes of the observer to the screen, or corresponding to the crossing of the optic axes at distances as above described. The triangular shaped frustrums or projections being such that they are corresponding to the lines of direction which are made by two lines crossing which are not more than the normal distance of two.

eyes, as l and 2 in Fig. 1.

The distance of these two points, l and 2, forming the right and left sides of the triangular shaped frustrums. j

When a single angle image an ordinary photograph or picture, is properly projected upon such a screen as above described, from position l 1n Fig. 1 1n relatlon to the screen,

the left eye being in position-2 and the right eye in position 3 as indicated in Fig. 1, the two eyes being horizontal in relation to the vertical triangular frustrums, suchv horizontal relation of the eyes to the vertical direction of the frustrums, at any vertical height of the two eyes when viewing such images projected upon such a screen, images of scenes or objects will produce perception of relief, solidity, space, etc., with more or less degree, according to thelaws of vision and according to the degree which such law or perception of relief etc., is complied with.

Each eye will be presented with factors that are very much like those met with in binocular vision, or, factors necessary. for perception of depth ,when looking at an actual-scene or object with both eyes. Both eyes will: 'see certain portions of picture which will represent corresponding points, uas indicated by sections 2 in Fig. 2; the left eye will see the non-corresponding points ofy j the 'fight' will Asee the non-corresponding points of picture as indicated by section 3 inI Fig. 2 as well as section 2.

By means `of'such a screen as described, a projection picture upon the screen is-divided into a number of sections and each of these sections is again subdivided into three sections each and accordingly as described the left eye will see more of the left side of image and .the right eye will see more "of the right side of ima e, while the centre of image will be seen by oth eyes, on each section of such a screen; and this is exactly what happens when examining Aa pair of stereoscopic images or photographs in the stereoscope or in looking at an actual scene inspace with both eyes.

I do not confine myself to the particular style of projection screen here shown, but -various other changes and modifications, within the skill of those versed in thementioned arts may be made in such a projection screen as has been shown and described herein without departing from the spirit of i claim A stereoscopic projection screen comprising a fiat base arranged vertically and a -plurality of elongated bodies disposed vertically upon the outer side of the base and spaced apart each body in cross-section having opposite sides converging outwardly ,in

intersecting planes radiating from points of vision spaced outwardly from the base and spaced a binocular distance apart, each body having a fiat outer face lying between said intersecting planes and between the point of intersection thereof and said base.

This specification signed and witnessed 40 this 20th day of January, 1922.

CHARLES BOUIN.

Witnesses:

MAY R. McEvoy, MARGARET PEABODY. 

